Mordant Spire, Ironbound Archipelago, Steaming Sea https://pathfinderwiki.com/wiki/Mordant_Spire

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Mordant Spire, Ironbound Archipelago, Steaming Sea https://pathfinderwiki.com/wiki/Mordant_Spire
Quote: Azlant. https://pathfinderwiki.com/wiki/Azlant
Quote: I’m afraid I must cut my expedition into this harsh, broken land short.
Sun Temple Colony, Azlant https://pathfinderwiki.com/wiki/Sun_Temple_Colony
Girl who hits like truck is 💖
Anyway I've got a BIGGOL crush on a guy who tried to kill us
Elion, god of exploration and discovery, from Paizo: Deities of Azlant by pindurski (Hugh Pindur)
Setting the Adventure in Place
The default setting of Ptolus is a small city, a port city. In theory, it could be placed just about anywhere.
Basic backstory says that the city was part of an empire that's crumbling. It also includes a powerful Christianity-like church that plays a major role in the adventure, and is made out to have strong influence throughout the empire. But as long as the church is a good-aligned religion, the empire and connection to it aren't really important.
The more important thing to consider about the setting is that Ptolus lies in the shadow of an impossibly-high stone spire, at the top of which lies the ancient tower fortress of the man who created the Banewarrens (and subsequently became an evil warlord). The spire was formed when the very earth itself reacted negatively to all of the evils stored in the Banewarrens (which are under the tower, and thus under the city), and thrust the tower away from it.
The fact that the Banewarrens are under the city is pretty important to some adventure points, and while it could be somewhere else entirely, I'm trying not to change much about the adventure if I don't have to. And that means the spire, which ends up being a location in the dungeon, also needs to exist in the city.
If I'm trying not to change Golarion much either to make them both fit, I can't reasonably use a major city centre. Because people would talk about that spire.
Upon learning of the Spire of Nex outside Absalom, I considered using that, since it already exists by a major city. However, not knowing enough about it, it sounded like too much about that spire was already established; it also stands a ways away from the city; and I know there's lots of existing information about Absalom that I don't want to change. In fact, I'd like to use the map of Ptolus included in the adventure as my city map (again, to change as little as possible), so again, it can't be a major existing city centre.
Andoran was another option for the setting, having seceded from a crumbling empire and being a generally cosmopolitan area, but a giant spire right on the Inner Sea would get a lot of attention. Plus there's another consideration: if this is an Azlanti structure, why is it so far from the ruins of Azlant?
Which made me wonder if I should place it in Varisia. It's a frontier area with several city centres, massive architectural ruins, and could easily include the City Under the Spire without causing much fuss. However, I'm not sure the backstory works as well in that case; since it featured in the very first Adventure Path, the history of that area is well-documented, and the creator of the Banewarrens would necessarily have featured in the Runelord conflicts. That would require a) too much research into the details of that history and b) too many alterations to the adventure.
Ultimately, I'm currently set on placing the Banewarrens in Kintargo in Cheliax. The town is described as a cosmopolitan port city, far enough from the centre of Cheliax politics to be a place where revolutionaries might meet in safety, meaning it won't be as closely affected by the current diabolical situation ruling the empire. Like Ptolus, it's on the edge of an empire that no longer has much influence over it.
It also seems like a city that doesn't have a lot of existing lore, so I can just swap in the Ptolus map. And while it's a port city for trade to Varisia and Arcadia, it seems far enough off the beaten path to host the giant spire without raising too many eyebrows. Plus, being on the western coast of Avistan, it could easily have been the location of an Azlanti colony, explaining why the creator of the Banewarrens was there. If there had been massive conflicts between good and evil, it could have been fairly localized, at least to that cape, and not affected Thassilon or the rest of Azlant very much.
It's looking pretty ideal. Plus if I want to through in some hell knights or something, I certainly can.